Your Invisible Friends – The Gut Bacteria.

You are not what you eat, you are your bacteria!
As we learned in the “Gut Bacteria…“, there are many times more bacteria living in and on you than there are cells in your body. Many of them are vitally important for your survival, producing nutritious compounds from otherwise indigestible fibers and other food compounds. They also keep your body safe from many pathogenic (disease causing) bacteria, viruses and fungi and help your enterocytes (the cells lining your intestines, absorbing nutrients and being a barrier between the contents of the intestines and the inside of your body) stay healthy and well functioning. It’s an intricate symbiotic relationship that we actually know very little about, but it’s a growing field of interest.
It seems that having a well functioning, balanced gut flora may keep you from a plethora of illnesses and diseases like IBS (Irritable Bowel Syndrome), IBD (Inflammatory Bowel Disease), Coealic (gluten intolerance), autoimmune diseases like Hashimotos thyroiditis, MS, and also brain disorders including Autism, ADHD, Depression, Schizophrenia and Alzheimers disease. It all seems to be linked to the health of the gut and it’s microscopic inhabitants.

But who are these bacteria?
I want to introduce you to some of the more common ones living in our guts. We all have our own setups, just like our fingerprint differ, but we all have these little creatures at least:

  • Lactobacilli is a large family of bacteria that got their name because they produce lactic acid and thus lower the pH of the gut membranes to about 5.5. The acidic environment is hostile for pathogenic bacteria and is crucial to keep them bad guys in check.
    The lactobacilli also produce substances that are anti-bacterial, -viral and -fungal, thus not giving the bad bacteria a chance to settle down in the gut. They also produce hydrogen peroxide (that’s right, the same substance used for bleaching hair), which is a powerful antiseptic compound. They interact with the immune system and stimulate a lot of different signal molecules and immune cells. They are vitally important for the health and renewal of your enterocytes, thus keeping the lining of your intestines in the best possible shape.
    The lactobacilli dosen’t only occupy the gut, they can be found in the mouth, throat, nose, genital area and vagina. They are one of the first bacteria to inhabit our intestines, since they are found in large numbers in the vagina and most us pass that way in the beginning of our lives. Human breast milk is full of the lactobacilli as well.
    A common name seen in commercial products, such as yoghurt is Lactobacilli Acidophilus. Some of the other common names are: Lactobacilli reuteri, bulgaricus and casei.
  • Bifidobacteria  consists of about 30 species, and are the most common bacteria in our gut. In a healthy baby they make up about 90-98% of the bacterial population in the bowel and are up to seven times more numerous than lactobacili in an healthy adult.
    These microscopic friends of our gut actually feed us. They actively produce vitamins (K, B1, B2, B3, B5, B6, folic acid, B12), organic acids, proteins and amino acids as well as assist in the uptake of vitamin D and minerals (calcium and iron).
    They also produce antibiotic-like substances, that keep the pathogenic bacteria in check, and interact with the immune system, just like the lactobacilli.
    Common names are: B. Bifidum, B. breve, B. infantis.
  • Escherichia Coli. This is a very large family of bacteria, of which some of the strains are pathogenic and can cause serious infections. There are, however, some physiological strains that are beneficial for us, when they are in their right place. They should only be found in our bowels and lower parts of our intestines. There they digest lactose, produce, amino acids, vitamin K and a bunch of the B vitamins. They secrete colicins. , which are antibiotic-like substances that keep the pathogenic flora in check. As with the other strains we have brought up, they also have an affect on the immune system, both locally and systemically.
    Having these physiological strains of E. Coli is the best way of not getting sick from the pathogenic ones.
  • Enterococcus/Streptococcus faecalis produce hydrogen peroxide which reduces the pH in the bowel and breaks down proteins and ferments carbohydrates without gas production and we can take up the related short chain fatty acids. These fatty acids are then used by the cells in the colon, by muscle cells and liver cells predominantly.
    These bacteria can become virulent and cause infections when not kept in check by other beneficial bacteria.
  • Bacillus subtilis are a group of bacterial strains that travel through our digestive system and help us on their way. They are soil bacteria and during our evolution we have ingested them through drinking water from wells and streams and also from eating soil particles with food. They are very stable bacteria, resistant to stomach acid, temperature changes and most antibiotics. They share their digestive enzymes, anti-viral, anti-fungal and anti-bacterial substances willingly and also have a stimulating effect on our immune system. They brake down rotting matter and suppress microbes that are putrefactive.

As stated before, the gut flora is different between each individual and it also changes with our diet, since they rely on the nutrient that go through the intestines. So long term dietary changes will affect the composition of the bacteria in your gut, which have impact on your enterocytes, what you absorb through the gut and how your immune system behaves. This is an interesting field of research, since long term dietary changes can be pivotal in improving health.

Read more:
http://www.scientificamerican.com/article/gut-second-brain/
http://www.ncbi.nlm.nih.gov/pubmed/23910373
http://www.ncbi.nlm.nih.gov/pubmed/23384445

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